We developed the spectral synthesis code Twinsyn to fit observed spectra of double-lined spectroscopic binaries with synthetic spectra derived from a grid of precalculated specific intensities. Twinsyn uses an unreduced chi-square goodness-of-fit statistic and a downhill simplex routine to determine the combination of temperature, surface gravity, rotational, and radial velocity parameters that delivers the best fit between the synthetic and observed spectra. We applied Twinsyn to observations made with the HYDRA multi-object spectrograph on the WIYN 3.5m for the WIYN Open Cluster Study (WOCS) to test its accuracy, and we report on the results here. This work was supported by the National Science Foundation's REU program through NSF Award AST-1004881.